/* 基础重置 */
:root {
    --primary-color: #4F7CFF;
    --primary-hover: #38BDF8;
    --text-main: #E8EDFF;
    --text-muted: #94A3B8;
    --bg-main: #0B1026;
    --bg-card: rgba(255, 255, 255, 0.05);
    --border-color: rgba(79, 124, 255, 0.5);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-main);
    background-color: var(--bg-main);
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* 布局容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 28px;
    background-color: var(--primary-color);
    color: white;
    font-weight: bold;
    border-radius: 8px;
    text-align: center;
    transition: background-color 0.3s, transform 0.1s;
    border: none;
    cursor: pointer;
}

.btn:hover {
    background-color: var(--primary-hover);
}

.btn:active {
    transform: scale(0.98);
}

.btn-large {
    padding: 16px 40px;
    font-size: 1.1rem;
}

.btn-secondary { background-color: rgba(255,255,255,0.1); border: 1px solid var(--border-color); }

.btn-secondary:hover { background-color: rgba(255,255,255,0.2); }

.hero-actions {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

/* 头部导航 */
header {
    background-color: rgba(11, 16, 38, 0.8); backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-color);
}

.logo a {
    color: inherit;
    text-decoration: none;
}

.main-nav {
    display: flex;
    gap: 25px;
}

.main-nav a {
    font-weight: 500;
    color: var(--text-main);
    transition: color 0.3s;
}

.main-nav a:hover {
    color: var(--primary-color);
}

/* 英雄区 (主视觉) */
.hero {
    text-align: center;
    padding: 100px 20px;
    background: transparent;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    font-weight: 800;
    line-height: 1.2;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* 通用区块标题 */
.section-title {
    text-align: center;
    font-size: 2.2rem;
    margin-bottom: 50px;
    font-weight: 700;
}

/* 核心优势卡片 */
.features {
    padding: 80px 0;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--bg-card);
    padding: 40px 30px;
    border-radius: 16px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    text-align: center;
    border: 1px solid var(--border-color);
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
}

.feature-card p {
    color: var(--text-muted);
}

/* 流媒体与AI支持 */
.support {
    padding: 80px 0;
    background-color: var(--bg-card);
}

.support-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    text-align: center;
}

.support-item {
    padding: 30px;
    background: rgba(255,255,255,0.02);
    border-radius: 12px;
    font-weight: 600;
    font-size: 1.2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

.support-item span {
    font-size: 2.5rem;
}

/* 定价表 */
.pricing {
    padding: 80px 0;
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.pricing-card {
    background: var(--bg-card);
    padding: 40px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    text-align: center;
    position: relative;
    display: flex;
    flex-direction: column;
}

.pricing-card.popular {
    border: 2px solid var(--primary-color);
    box-shadow: 0 10px 15px -3px rgba(37, 99, 235, 0.1);
}

.popular-badge {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: bold;
}

.pricing-card h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.price {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.price span {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: normal;
}

.pricing-features {
    text-align: left;
    margin-bottom: 30px;
    flex-grow: 1;
}

.pricing-features li {
    margin-bottom: 12px;
    padding-left: 24px;
    position: relative;
}

.pricing-features li::before {
    content: "✓";
    color: #10b981;
    position: absolute;
    left: 0;
    font-weight: bold;
}

/* 用户评价 */
.reviews {
    padding: 80px 0;
    background-color: var(--bg-card);
}

.review-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.review-card {
    background: var(--bg-main);
    padding: 30px;
    border-radius: 16px;
    font-style: italic;
    color: var(--text-muted);
}

.reviewer {
    margin-top: 20px;
    font-weight: bold;
    font-style: normal;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 10px;
}

.reviewer::before {
    content: "";
    display: block;
    width: 30px;
    height: 30px;
    background: var(--primary-color);
    border-radius: 50%;
    opacity: 0.2;
}

/* FAQ */
.faq {
    padding: 80px 0;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

details {
    background: var(--bg-card);
    margin-bottom: 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}

summary {
    padding: 20px;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    list-style: none;
    position: relative;
}

summary::-webkit-details-marker {
    display: none;
}

summary::after {
    content: "+";
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    color: var(--text-muted);
}

details[open] summary::after {
    content: "-";
}

details p {
    padding: 0 20px 20px;
    color: var(--text-muted);
}

details[open] summary {
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 15px;
}

/* 页脚 */
footer {
    background-color: transparent; border-top: 1px solid var(--border-color); color: var(--text-muted);
    padding: 60px 0 30px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.footer-links a {
    transition: color 0.3s;
}

.footer-links a:hover {
    color: white;
}

.copyright {
    font-size: 0.9rem;
}

/* 独立页面通用样式 */
.page-content {
    background: var(--bg-card);
    padding: 40px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    margin: 40px auto;
}

.page-content h1 {
    margin-bottom: 30px;
    font-size: 2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
}

.page-content h2 {
    margin: 25px 0 15px;
    font-size: 1.4rem;
}

.page-content p {
    margin-bottom: 15px;
    color: var(--text-muted);
}

.page-content ul {
    margin-bottom: 15px;
    padding-left: 20px;
    list-style-type: disc;
    color: var(--text-muted);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        height: auto;
        padding: 15px 0;
        gap: 15px;
    }
    
    .main-nav {
        gap: 15px;
        font-size: 0.95rem;
    }

    .hero h1 {
        font-size: 2.2rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }

    .section-title {
        font-size: 1.8rem;
    }

    .feature-grid, .pricing-grid, .review-grid {
        grid-template-columns: 1fr;
    }

    .footer-links {
        flex-direction: column;
        gap: 15px;
    }
    
    .btn {
        display: block;
        width: 100%;
    }
    
    .hero .btn {
        display: inline-block;
        width: auto;
    }
    
    .page-content {
        padding: 20px;
        margin: 20px auto;
    }
}

/* 深空背景动效层 */
.space-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    pointer-events: none;
    overflow: hidden;
    background: #0B1026;
}

.space-stars {
    position: absolute;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(1px 1px at 15% 25%, #fff, transparent),
        radial-gradient(1px 1px at 35% 55%, #fff, transparent),
        radial-gradient(1.5px 1.5px at 65% 15%, #fff, transparent),
        radial-gradient(1px 1px at 85% 85%, #fff, transparent),
        radial-gradient(2px 2px at 95% 35%, #fff, transparent),
        radial-gradient(1px 1px at 45% 75%, #fff, transparent),
        radial-gradient(1px 1px at 25% 95%, #fff, transparent),
        radial-gradient(1.5px 1.5px at 75% 65%, #fff, transparent);
    background-size: 250px 250px;
    opacity: 0.3;
}

.space-nebula {
    position: absolute;
    top: 15%;
    left: 20%;
    width: 70vw;
    height: 70vh;
    background: radial-gradient(circle, rgba(79, 124, 255, 0.12) 0%, rgba(120, 100, 255, 0.04) 40%, transparent 70%);
    border-radius: 50%;
    filter: blur(60px);
    animation: nebula-float 30s infinite ease-in-out alternate;
}

@keyframes nebula-float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(15vw, -5vh) scale(1.15); }
}

.space-twinkle {
    position: absolute;
    width: 2px;
    height: 2px;
    background: #fff;
    border-radius: 50%;
    box-shadow: 0 0 5px #fff, 0 0 10px var(--primary-color);
    animation: twinkle 3.5s infinite ease-in-out alternate;
}
.space-twinkle.t1 { top: 12%; left: 28%; animation-delay: 0s; }
.space-twinkle.t2 { top: 45%; left: 78%; animation-delay: 0.5s; }
.space-twinkle.t3 { top: 80%; left: 15%; animation-delay: 1.2s; }
.space-twinkle.t4 { top: 22%; left: 85%; animation-delay: 2.1s; }
.space-twinkle.t5 { top: 62%; left: 45%; animation-delay: 0.8s; }
.space-twinkle.t6 { top: 88%; left: 75%; animation-delay: 1.7s; }
.space-twinkle.t7 { top: 35%; left: 10%; animation-delay: 2.5s; }

@keyframes twinkle {
    0% { opacity: 0.25; transform: scale(0.8); }
    100% { opacity: 1; transform: scale(1.2); }
}

.space-meteor {
    position: absolute;
    top: -5%;
    left: 15%;
    width: 120px;
    height: 1px;
    background: linear-gradient(90deg, rgba(255,255,255,0), rgba(255,255,255,0.8), rgba(255,255,255,1));
    transform: rotate(16deg);
    opacity: 0;
    animation: meteor-fall 9s infinite linear;
}

@keyframes meteor-fall {
    0%, 90% { opacity: 0; transform: translate(0, 0) rotate(16deg); }
    91% { opacity: 1; transform: translate(0, 0) rotate(16deg); }
    100% { opacity: 0; transform: translate(60vw, 22vh) rotate(16deg); }
}

@media (prefers-reduced-motion: reduce) {
    .space-nebula, .space-twinkle, .space-meteor {
        animation: none;
    }
}

/* Phase 2 A11y & CSS Fixes */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-color);
    color: white;
    padding: 8px;
    z-index: 1000;
    transition: top 0.2s;
}
.skip-link:focus {
    top: 0;
}
:focus-visible {
    outline: 2px solid var(--primary-hover);
    outline-offset: 2px;
}
.page-content, .article-body, p {
    word-break: break-word;
    overflow-wrap: anywhere;
}
section[id] {
    scroll-margin-top: 80px;
}